A Definition
a
- noun
- a metric unit of length equal to one ten billionth of a meter (or 0.0001 micron); used to specify wavelengths of electromagnetic radiation
- any of several fat-soluble vitamins essential for normal vision; prevents night blindness or inflammation or dryness of the eyes
- one of the four nucleotides used in building DNA; all four nucleotides have a common phosphate group and a sugar (ribose)
- (biochemistry) purine base found in DNA and RNA; pairs with thymine in DNA and with uracil in RNA
- the basic unit of electric current adopted under the Systeme International d'Unites; "a typical household circuit carries 15 to 50 amps"
- the 1st letter of the Roman alphabet
- the blood group whose red cells carry the A antigen
"A" in song lyrics
See how a is used in real songs:
-
"Can't nothin' hold A"
(11/5 f/) Taydatay — Roll 'Em Up [Edit] -
"Finally figured we'd share a"
2 Hungry Bros. present 8thW1 f/ Janelle Renee — More Go -
"Coolin' with the fellas while downin' a 40"
2 Live Crew — Hangin' Out
Words that rhyme with a
Usage tips for "a"
Understanding the precise definition of a word helps you use it with confidence. When using "a" in your writing, consider whether you need the word itself or one of its synonyms — subtle differences in meaning can change the tone of a sentence. If you're writing poetry or song lyrics, check the rhymes for a to find words that pair well.